Signs of trouble have been apparent at U.S. Consulate sites in Mexico

A man spray-paints a sign that reads in Spanish “People from Juarez, let’s defend ourselves. Get out army” at a protest against the upcoming visit by Mexico’s President Felipe Calderon.

CIUDAD JUAREZ, Mexico — The danger signs had been mounting. The U.S. Consulate in Ciudad Juarez recently shut down for a bomb threat (which proved false). Federal police guards were redoubled. Officials working at the diplomatic mission saw their movements being gradually restricted, some parts of the city deemed too dicey to frequent.

But the Americans leaving a weekend child's birthday party probably made the same calculations that many living in Mexico make. It was broad daylight. We'll be traveling on major roads. It is probably safe enough.

Lesley Enriquez, a U.S. consular official, and her husband, Arthur H. Redelfs, were driving home to El Paso, Texas, just across the border, when suspected drug gangs intercepted their car and shot them to death Saturday afternoon. Their baby daughter, crying in the back seat, survived unharmed.

At almost the same time, in a separate but similar car leaving the same party, Jorge Alberto Salcido was also shot to death. Two children with him were injured. Salcido was a Mexican citizen married to a Mexican who works at the consulate.

The drive-bys were a rare attack on U.S. officials in Mexico's raging drug war, which has claimed at least 18,000 lives in slightly more than three years.

As the FBI joined the investigation Monday, Mexican authorities said they believed the victims were targeted but it remained to be determined why. U.S. officials were cautious. "At this point, we don't have information that says they were targeted because of their employment at the U.S. consulate," said Andrea Simmons, an FBI spokeswoman in El Paso. "It's a possibility, but so far nothing has indicated it was directly related to their employment. … In the past, we have had cases that turned out to be mistaken identity."

State Department officials said they were not aware of specific threats against any consular employees.

But the signs of trouble were apparent, here and elsewhere along Mexico's northern border with the United States. In Reynosa, in neighboring Tamaulipas state, the U.S. Consulate was closed earlier this month because of raging gun battles, and travel advisories were issued against driving on interstate highways because of the violence. The consulate in Monterrey has come under grenade attack.

The consulate in Ciudad Juarez was closed Monday for a holiday. The American flag was at half staff.

A journalist was killed in southern Mexico, the fourth slain in the country this year. The leader of the journalists union in Guerrero state said Evaristo Pacheco worked for the regional weekly Vision Informativa. Police said he was shot to death Friday after being snatched from a nightclub in the state capital, Chilpancingo.

Fast facts

Journalist killed

A journalist was killed in southern Mexico, the fourth slain in the country this year. The leader of the journalists union in Guerrero state said Evaristo Pacheco worked for the regional weekly Vision Informativa. Police said he was shot to death Friday after being snatched from a nightclub in the state capital, Chilpancingo.